1. Field
This application relates to portable structures for mounting drills in fixed position for operation, and more specifically, to portable means to secure a drill in an adjustable position for drilling into a workpiece, especially heavy-duty internal combustion engines.
2. State of the Art
Many common machine shop jobs, such as removing broken or sheared bolts and threading bolt holes, require drilling operations. A problem sometimes encountered in these jobs is the difficulty in bringing the workpiece to a drilling mechanism such as a drill press. A workpiece may be very large or heavy, or may be in a remote location such as in building erection, so that considerable effort is required to move the workpiece to the drilling mechanism. Further, if the workpiece is very massive, it may not fit under the drilling head of a typical drilling mechanism.
Mounting an irregularly shaped workpiece to a conventional drilling mechanism may also be problematic. The workpiece may have a shape making it difficult or impossible to mount the workpiece in position for drilling. In some instances, the drill site may be partially obstructed or concealed so that conventional drilling techniques are not possible. Such a problem exists if a drilling operation is required on the underside of a piece of machinery or equipment.
Many workpieces requiring drilling operations are components of a larger assembly. Conventional drilling mechanisms require that either the entire assembly be moved to the drill, or the component be removed from the assembly and brought to the drill. In some instances, for example a cylinder head on an automobile or truck engine, either of these options is laborious. If the drilling operation is on a component of a machine tool used in a production setting, expensive down-time may be incurred while the machine is disassembled and brought to the drilling apparatus.
It would be preferable in these and other situations, to bring the drilling mechanism to the workpiece instead of vice versa. Machines could be left in an assembled position while the drilling operation is performed at the machine site. Heavy duty equipment could be repaired in the field rather than transporting the equipment to a repair shop. If a component of an assembly required a drilling operation, disassembly would not be required if the drilling operation could be performed with the component in the assembled position.
A mobile support for an electric drill is disclosed in U.S. Pat. No. 3,417,949 to Waber. The Waber invention adjustably mounts a drill on a wheeled carriage which can be positioned next to a workpiece. Several adjustment means are provided to position the drill for the drilling operation. The Waber invention does not mount to the workpiece, but is brought to and positioned near it so that an abutment chain can be fastened around the workpiece.